Heating device for molten materials



Oct. 2, 1951 R. L. NALL 2,569,824

HEATING DEVICE FOR MOLTEN MATERIALS Filed Feb. 12, 1948 2 Sheets-Sheet 1m T la 24 7 /90 INVENTOR 4 05527" I A1414 ATTORNEY Oct. 2, 1951 R. L.NALL 2,569,824

HEATING DEVICE FOR MOLTEN MATERIALS Filed Feb. 12, 1948 2 Sheets-Sheet 2Tia a.

INVENTOR &es:? 4. A4444.

ATTORN EY Patented Oct. 2, 1951 UNITED STATES QFFICE 2,569,824 HEATINGDEVICE FOR. MOLTEN MATERIALS Robert L. Nall, New Orleans, La.) assignorto The Patent and Licensin g Corporation, New York,

N. Y., a corporation of Massachusetts Application February 12, 1948,Serial No. 7,812

4 Claims. 1

This invention relates to a device for heating liquid materials.Although not confined thereto, the invention is particularly concernedwith a device which is adapted for use as a superheater for heatingliquefied bitumens, such as asphalt, to relatively high temperatures.

In the manufacture of asphalt-impregnated floor coverings and roofingmaterials such as roll roofing, shingles and the like, a continuous webor foundation sheet of fibrous felt is saturated by immersion in a bathof molten asphalt. When the impregnated web isto be used for thepreparation of roof coverings, it is further processed to provide theweb with a coating of relatively high melting point asphalt and aweather surface of mineral particles embedded in the coating. Inthecourse of the saturation step the felt web is guided through a bathof molten saturant by passing the web over upper and lower sets of guiderolls, the lower set being submerged in. the saturant adjacent thebottom of the saturator tank. In order to obtain rapid and eiieictivesaturation of the web, the asphalt saturant in the tank is maintained ata relatively high .temperature, i. e., 450 to 525 F. The felt web beingcontinuously introduced into the hot molten asphalt, however, has amarkedzcooling effect on the saturant and, of course, the continuousabsorption of asphalt from the saturator bath by the web consistentlydepletes the supply of .saturant. It is accordingly necessary to provideheating means which will continuously .and rapidly reheat the cooledasphalt to the desired elevated temperature and which will also heat themake.- up asphalt added to the saturator system.

Heating units which are commonly used in roofing plants for maintainingthe saturant at elevated temperatures are tube-type refractory heaterswherein the asphalt is pumped through a tube positioned in a heatedchamber. Such heating units have the disadvantage of being comparativelylarge and requiring extensive floor areas to accommodate them. Further,the refractory brick work involved in the construction of such heatersplaces a heavy weight upon the foundation and cracking of the brick dueto settling is frequently encountered.

It is an object of this invention to provide an improved heating deviceadapted to heat molten liquids continuously and efficiently torelatively high temperatures and which requires a minimum of floorspace, is relatively light upon its foundation and is not susceptible toinjury from normal settling. l

Itis a furtherobject of the invention to pro- (c1. nit-343.5)

2 vide a heating :device .ofvthe character indicated which. is adaptedto bensed'in conjunction ,th the saturator unit of aroofin machine tomain tain the saturant therein at a temperature of 450 to 525 F.

Other objects and advantages of the invention will be apparent .from'the'detailed description which is to follow and from therdrawings :inwhich,

Fig. 1 is a diagrammatic view ofa heater con,- structed according to theinvention. showingthe manner in which it may be -,associate c l.with a ifelt saturator. and witha makeeupasp halt supply; a

Fig. 2 is a view in elevation: of the heater with a portion thereofbroken away to show the ar rangementiof the .flues;

Fig. 3 is a horizontalsection taken along the line 33 of Fig. 2;

Fig. 4 is a sectional view along theline ;44 of :Fig. 3 showing: the arangement of names and Fig; 5 is a: sectional view ,showing the method.ofsecuring the fines tosthe supporting structures.

Referring to the drawings, the numeral Ii) designates generallyatankwhich forms the body or casing of theiheater and-which comprises amdricalwall l2. proyided with heads formed by hemispherical walls. and lSsecured as by welding to :theupper and lower ends, respectively, ofwall 12; A'supporting structure for the tank in is provided b e gird lle ur -t t e ut sideof wall 12 and vertical columns 18 jointed to girder.Flanged inletnozzles 22 and {Bare providedin hemispherical wall 15 andcylindricalwall 12, respectively, and a flanged outlet nozzle 24 isprovided in hemispherical iwalll 114. In order to; prevent surging ofthe liquid-being heated .asrit ,is pumped through the heater the tank Itis providedw i bei g 5 and 'vbish extend w rdl adiac n l .22 ou l t 5respectively, each hafiie being .formedby two .outwardly divergingperforated plate's'ianda' liorizontal perforated circul arflplatesecured to the outerendsthereotflas shown in Fig. 2'. To permit accessto. the inte jiq of tank H), cov red manholes 21 and 2,8 are termed inwall 14, and

covered manholes 129 and 30 areprovidedi'n wall I 2 and wall 15,respectively.

The liquid; gasphai p as itpasses upwardly through the tank l 0 isheated by direct contact with a series ofparallel, horizontally-disposedsinuous flues through which hot. .combustion gases are passed.Theseiflues inthe embodiment illustrated are .arrangedwin .threebanks:;of= four fluesreach; the fines the .upper, intermediate and lowerbankszbeing. de'signatedailil, 34 ands,

respectively. It is a feature of the invention that each flue has anindependent source of heat and that each flue passes through the tank inthe same plane and substantially in a plane parallel to the planes ofthe other flues. The ends of the flues 32 are provided with flanges 3'8and 39, the flanges 38 being bolted to flanged ends 4| of flue outlets42, which are secured asby welding in suitable'openings in wall 12, andflanges 39 being bolted to flanged ends 44 of flue inlets 45, alsosecured in openings in wall l2. Flues 34 and 36 are similarly attachedto flue outlets 50 and 52, respectively, and flue inlets 54 and'56,respectively. Parallel angle irons 58 and 59 which extend across theinterior of tank Ill-support the flues 32, 34 and 36 which are securedto the angle irons by U-bolts 60.

Hot combustion gases are received in the flues 32 from burners 62, anindividual burner being positioned adjacent each flue inlet 45.Similarly, each of the flues 34 and 36 is heated by gases from burners64 and 66, respectively, positioned adjacent each flue inlet 54 and 56,respectively. The burners 62, 64 and 66 are not per se a part of theinvention and may be any suitable gas or oilflred burner or the like.The combustion gases as they are discharged from the flues enter stackswhich vent the gases to the atmosphere, an independent stack beingprovided for each bank of flues. The gases leaving flues 32 pass throughflue outlets 42 into a stack 16 and the gases in flues 34 and 36 arevented through stacks Ill and 12, respectively. Additional stacks may beprovided, if desired, as for example, an individual stack for each flue.A forced draft is induced in the banks of flues by suitable blowers 16a,Ila and 12a positioned in stacks 10, H and I2, respectively.

It will be observed that each of the three banks of flues is slightlyoffset horizontally with respect to the other two banks. Thisarrangement of the flues insures more intimate contact of the liquidwith the flues as it progresses upwardly through the'tank Iii.Exteriorly of tank 10, the banks of flue inlets and flue outlets are, ofcourse, similarly offset with respect to one another.

Referring particularly to Figs. 3 and 4, it will be observed that twooblique bafiles areprovided to direct the liquid onto the flues inthat-portion of the tank where the flues are furthest from the wall 12.A baffie 15, having a flange 16 which is bolted to the inner side ofwall I I, is positioned just below the upper bank of flues 32 and abaflle I1 having a flange 18 is similarly placed 'just below flues 34. 7

Referring particularly to Fig. l, the numeral 80 designates a saturatorunit in which is maintained a pool of liquid asphalt 82 through which aweb 83 is guided in the usual manner by upper rollers 85 and lowerrollers 86. The asphalt in the saturator 80 is returned to tank ID to bereheated'througha pipe 88 which extends from the lower part of thesaturator 80 to inlet 23, the asphalt being pumped through the pipe by apositive pressure pump 89. A pipe'90 connected to outlet 24 conducts theheated asphalt back to saturator 80 after it has'passed through the tankIll and has been heated by the flues therein. An asphalt supply tank 92which furnishes molten make-up asphalt to replace the asphalt absorbedby, the web passing through the saturator is connected to inlet122 byapipe 94 which is provided .with a positive pressure pump. 93. ,The.asphalt. from makeeup tank92 4 may be continuously or intermittentlypumped into tank H).

An asphalt heatin and circulating system is thus provided in which theheating device of the invention continuously heats the cooled asphaltfrom the saturator and at the same time heats the make-up asphalt as itis supplied to the system. In operating the heater, one or more banks offlues may be fired, depending upon the amount of heat to' be supplied tothe liquid being pumped through the heater. When heavy grades of feltare being saturated, for example, the temperature drop caused by thecooling effect of the felt is greater than that caused by a light weightfelt, and accordingly, all three banks must generally be fired,particularly when the felt is being run through the saturator at a highrate of speed. When a light weight felt is being saturated, firing of asingle bank may be sufficient to keep the asphalt at the desiredtemperature. Since each flue is fired by an independent burner it willbe apparent that the heater of the invention has great flexibility andmaybe utilized to accommodate a large variety of operating conditions.When the heater is in operation, the tank I0 is filled with liquid andthe flues are, therefore, submerged at all, times whereby efficientheating is promoted.

While the drawings and the foregoing descrip-; tion of one embodiment ofthe invention relate to a heater having a vertical casing, the device ofthe invention may also be effectively embodied in a horizontal casing.It will be apparent that various other changes may be made withoutdeparting from the scope of the invention as defined in the appendedclaims and it is therefore intended that the foregoing shall beinterpreted in an illustrative and not in a limiting sense.

I claim:

l. A device for continuously heating molten asphalt and the like totemperatures of the order of 450 F. to 525 F., comprising a tank'adaptedfor continuous upward pass-age therethrough of the molten material to beheated, and a plurality of individually-fired, sinuous heating flueshorizontally disposed in said tank in substantially parallelvertically-spaced relationship, the said flues being arranged in atleast two verticallyspaced banks, the flues of one bank beinghorizontally offset with respect to the flues of the adjacent bank, andeach of said flues being arranged to extend over a substantial portionof the internal horizontal cross-sectional area of said tank whereby topermit intimate contact between the exterior surface of the flues andthe inolllien material passing upwardly through said 2. A device forcontinuously heating molten asphalt and the like to temperatures of theorder of 450 F. to 525 F., comprising a tank adapted for continuousupward passage therethrough of the molten material to be heated, aplurality of individually-fired, sinuous heating flues horizontallydisposed in said tank in substantially parallel vertically-spacedrelationship, the said flues being arranged in at least twoverticallyspaced banks, and a, stack adjacent each bank of flues adaptedto receive the exit gases therefrom, each of said flues being arrangedto extend over a substantial portion of the internal horizontalcross-sectional area of said tank whereby to permit intimate contactbetween the exterior surface of the flues and the molten materialpassing upwardly through said tank.

3. A device for continuously heating molten asphalt and the like totemperatures of the order of 450 F. to 525 F., comprising a verticaltank adapted for continuous upward passage therethrough of the moltenmaterial to be heated, an inlet for the liquid in the lower portion ofsaid tank, an outlet for the liquid in the upper portion of said tank, aplurality of individuallyfired, sinuous heating flues horizontallydisposed in said tank in substantially parallel verticallyspacedrelationship, the said flues being arranged in at least twovertically-spaced banks, the tines of one bank being horizontally oifsetwith respect to the fines of the adjacent bank, and each of said fluesbein arranged to extend over a substantial portion of the internalhorizontal crosssectional area of said tank whereby to permit intimatecontact between the exterior surface of the hues and the molten materialpassing upwardly through said tank.

4. A device for continuously heating molten asphalt and the like totemperatures of the order of 450 F. to 525 F., comprising a, verticaltank adapted for continuous upward passage there through of the moltenmaterial to be heated, an inlet for the liquid in the lower portion ofsaid tank, an outlet for the liquid in the upper portion of said tank, aplurality of individuallyfired, sinuous heating flues horizontallydisposed in said tank in substantially parallel verticallyspacedrelationship, the said flues being arranged in at least twovertically-spaced banks, the flues of one bank being horizontally offsetwith respect to the fines of the adjacent bank, and a stack tank.

ROBERT L. NALL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 793,472 Thorbus June 27, 19051,016,411 Isaacs Feb. 6, 1912 1,226,379 Riley May 15, 1917 1,249,480Pfiugfelder Dec. 11, 1917 1,579,193 Chipman Mar. 30, 1926 1,908,932Tiburtius May 16, 1933 1,932,793 Lough Oct. 31, 1933 1,949,471Hildebrand et a1. Mar. 6, 1934 2,137,693 Lundt Nov. 22, 1938 2,176,869Childs Oct. 24, 1939 2,321,109 Sellers June 8, 1943 2,367,018 Gerges a-Jan. 9, 1945 FOREIGN PATENTS Number Country Date 271,567 Great BritainMay 26, 1927

